Spin-on Deposition of Amorphous Zeolitic imidazolate Framework (aZIF) Films for Lithography Applications

Amorphous zeolitic imidazolate framework (aZIF) films have been recently introduced as resists for electron beam and extreme ultraviolet lithography (EBL and EUVL). aZIFs are also being considered for separation applications, including thin film membranes. In this respect, methods for thin film aZIF deposition are needed. However, the reported methods are currently based on highly empirical trial-and-error approaches that hinder control of film composition, thickness, and uniformity as well as scale-up and transferability to different coating geometries from the ones they have been originally developed for. A method for depositing aZIF films with controllable thickness using dilute precursors mixed immediately before encountering the substrate is presented. Importantly, the method is amenable to quantitative analysis by computational fluid dynamics to extract intrinsic deposition rates and limiting reactant transport diffusivities, enabling predictive equation-based modeling of the aZIF film deposition process. This allows the deposition method to be adapted for spin coating on silicon wafers, enabling the production of aZIF films with consistently controlled thickness. Using this approach, high-quality aZIF films are prepared, and high-resolution resist performance is demonstrated.